The benefit is a 25% strength increase and 50% duration increase to all spells against undead. This effect applies to weapon enchantments as well.
Becoming a vampire will make the Dragonborn undead and thus certain spells, shouts and enchantments will increase in potency. Negative effects will also be affected, however, such as Weakness to Fire. Some perks are also affected if chosen after obtaining the Necromage perk.
Affected spells and perks
- All enchantments placed on clothing/armor increase by 25% in magnitude.
- Dead Thrall: Increase the maximum level deceased vampire targets can be raised past 50.
- The Ritual Stone: Increase the maximum level deceased targets can be raised past 75.
- Atronach: Increase spell absorption chance from 30% to 37.5%.
- Snakeblood: Increase poison resistance from 50% to 62.5%
- Dual Flurry: Increase overall speed by 25%.
- Extra Pockets: Increase carry weight a further 25%.
- Fists of Steel: 25% more damage per armor rate.
- Magic Resistance: Increase magic resistance by 25%.
- Power Shot: Increase stagger by 25%
- Steady Hand: Time moves 25% slower.
- Quick Shot: Increase overall speed by 25%.
- Recovery: Increase magicka regeneration by 25%.
- Wind Walker: Increase stamina regeneration by 25%.
- The Atronach Stone: Increase spell absorption from 50% to 62.5%
- Shielding spells (e.g. without Alteration perks, Ebonyflesh provides 125 armor instead of 100, and lasts for 90 seconds instead of 60).
- This effect is multiplicative when combined with the Mage Armor perk (e.g. the 125 armor from Ebonyflesh would become 250 at the first level of the Mage Armor perk); the extended duration also stacks with Alteration perk Stability (additional 50% duration for a total of 120 seconds). Affects Dragonhide duration stacking with Stability, but armor provided unaffected.
- Muffle: Increase duration by 50%.
- Invisibility: Increase duration by 50%.
- The Steed Stone: Increase carry weight by +25, though the description still says +100.
- The Lord Stone: Increase armor resistance from 50–62, and increase magic resistance from 25% to 31.25%.
- Dragonskin: Increase absorption to 62% and duration to 90 seconds.
- Created potions: Increases effect by 25% and the duration (if applicable) by 50%